Cellular mobile telephone services are currently one of the most rapidly expanding types of communication services. They have been in operation in the continental United States for nearly a decade and have been offered in many other parts of the world for several years.
Whereas cellular mobile telephone services were once limited to relatively small geographic home areas, they have since evolved to permit expanded service across state and national boundaries through “roaming” agreements. This expansion has served the commercial objectives of mobile telephone service providers by providing roaming mobile subscribers the ability to freely and quickly automatically originate and receive telephone calls from other fixed or mobile stations in the network.
Roaming services have allowed cellular subscribers who travel or “roam” away from their home markets to use their mobile phones in these new markets. Typically, when a subscriber first enters a roaming market or “powers up” the cellular telephone in a roaming market, the phone's unique MIN and ESN are transmitted to a serving carrier of the serving market. These numbers identify to the serving carrier that the subscriber whose access codes have been transmitted is not a local subscriber. Utilizing an IS-41 network, the server requests registration data from the subscriber's home carrier which corresponds to the received MIN/ESN. This registration data is delivered via the IS-41 network back to the serving market to provide information to the serving carrier regarding the subscriber's call features and restrictions and to enable the carrier to make a decision whether or not to provide service. The system then validates that a particular MIN/ESN is entitled to roaming privileges. Optionally, these roaming systems can also include functionality to guard against clone fraud which in recent years has dramatically increased.
One known system for preventing and detecting cloning fraud is provided by GTE Telecommunication Services, Inc. (GTETSI). GTE TSI provides a clearing-house validation service by maintaining a “positive” database of valid subscriber MIN/ESNs and a “negative” database of invalid subscriber MIN/ESNs. When a call is received by the GTE TSI system, a lookup is performed against the positive and negative databases to determine if the MIN/ESN combination is valid. If not, the MIN/ESN is entered into the negative database. Thus, this systems provides a subscriber with some protection against fraudulent use of the subscriber's ESn and MIN.
In addition to roaming services, the use of mobile telephones has also expanded in part due to new services, such as prepaid calling services, that allow a whole new segment of users to take advantage of mobile voice and data services. For example, users that lack credit histories or users that want to provide third parties with a mobile telephone, but still retain some control over the cost of providing such services, may subscribe to prepaid telephone services, allowing them to pay in advance for telephone calls. These systems operate by providing the subscriber with a debit account or a debit card that the subscriber can draw finds from to pay for a telephone call. Each time the prepaid subscriber makes a call, the call is routed through a prepaid platform. At the platform, the funds available to the subscriber are checked, and the subscriber is allowed to make a call while funds are available. As funds become depleted, the prepaid platform issues an audible warning to the subscriber and eventually terminates the call. Thus, the subscriber can budget the amount of money that the subscriber wants to spend on phone services and can use the prepaid service as a way of limiting expenditures and reducing cost overruns.
Although roaming and prepaid services have become very popular within the mobile phone users, these services exist separately, and therefore a prepaid user has not had the ability to use their phone service outside of their home market. Specifically, the roaming systems that exist today can support a traditional credit subscriber by keeping track of that subscriber's use of the serving market's circuits and subsequently billing the subscriber through their home market provider. However, most roaming systems do not have access to the debit account information for a prepaid customer, nor do they have access to a prepaid platform that can warn the subscriber as the funds begin to deplete, or terminate a call once the finds are spent. Thus, most remote serving markets cannot support a roaming prepaid subscriber.
Accordingly, there exists a need for a roaming system that can provide seamless roaming to a prepaid subscriber.